Use footnote (<fn>) to annotate text with
notes that are not appropriate for inclusion in line or to indicate the source
for facts or other material used in the text.
Footnote content is always skipped at the place where it was entered,
and reproduced elsewhere, according to these rules:
- A footnote with no given id attribute is a single-use footnote.
Upon output, it generates a number as a superscript "callout" that is
linked to the placement of the footnote, usually at the bottom of the immediate
printed page or at the end of the Web article. Subsequent footnotes in the
same topic will have the next number in sequence for their callouts. If you
enter a particular character in the callout attribute
for the footnote, that character will be used as the superscript "callout" that
is linked to the placement of the footnote.
- A footnote entered with an id attribute is a use-by-reference footnote.
Upon output, it does not appear anywhere unless it has been referenced using
an <xref> with the type attribute
set to "fn". The same callout behaviors will apply.
- Ordinarily, a footnote in one topic can't be referenced in another topic.
The previous behaviors are local to each topic. But by using the <conref>
mechanism, you can instance another topic's footnote into the local topic
where it will then follow those behaviors:
- If you use <fn conref="thatid"></fn> all by itself,
the result will be the same as the single-use footnote entered literally in
the same location.
- If you use <fn conref="thatid" id="thisid"></fn>,
then <xref href="thisid" type="fn"/>, the result will
be the same as the use-by-reference model described before.
Contained by
section,
example,
p,
note,
lq,
sli,
li,
itemgroup,
dd,
figgroup,
pre,
lines,
ph,
stentry,
entry,
prereq,
context,
cmd,
info,
tutorialinfo,
stepxmp,
choice,
choptionhd,
chdeschd,
choption,
chdesc,
stepresult,
result,
postreq,
refsyn,
proptypehd,
propvaluehd,
propdeschd,
proptype,
propvalue,
screen,
codeblock,
pd
Attributes
Name |
Description |
Data Type |
Default Value |
Required? |
callout |
Specifies what character is used for the footnote link, for example
a number or an alpha character. Numbers are the default. You could also specify
a graphic for the footnote callout during output processing. |
CDATA |
#IMPLIED |
No |
%univ-atts; (%select-atts;, %id-atts;, translate, xml:lang) |
A set of related attributes, described at univ-atts |
parameter entity |
PE not
applicable |
Not applicable
|
%global-atts; (xtrf, xtrc) |
A set of related attributes, described at global-atts |
parameter entity |
PE not
applicable |
Not applicable
|
class, outputclass |
Common attributes described in othercommon |
Example
This markup:
The memory storage capacity of the computer is
2 GB<fn callout="#">A GB (gigabyte) is equal to
1 million bytes</fn> with error correcting support.
produces
this output:
The memory storage capacity of the computer is 2 GB# with error correcting support.
Note: Footnote support may vary between different output types, depending
on conventions and capabilities. For example, PDF output may lack support
for the callout attribute, or footnotes may be collected as endnotes
for certain types of Web publications.